295 will be too wide for the 9.5" rear rim (You will lose steering response) and you are better off maintaining the 20mm stagger to keep the tire diameter stagger the same (DSC will cut in more if the stagger is increased).

The difference between 245/265 and 265/285 is very small, by the way. You will lose steering response and gain a bit more total grip.

As you suggest, if the difference is minimal, the last thing I want is reduced steering response. I have posted here many times that the slow steering, the overboost, and the lack of feel is the only problem I have with the car.